I'll try it again. Mary did not give birth IN ETERNITY to the Second Person of the Trinity. Mary is a creature, and had a beginning in time, just like you and me. The eternal Son of God did not take His Divine nature from Mary.
She did, however, conceive in her womb the Son of God made Man. He is still the eternal Son of God, as well as Man.
I did not say that the “Son from eternity” ceased being so when He became Incarnate in Mary's womb. I merely said that she was not His mother FROM ETERNITY. She became His mother in time. That's a huge distinction.
It was I who misunderstood your comment. I too will try again.
If the Son of God, Second Person of the Trinity was such even before Mary existed then in what sense is Mary mother to God, Second Person of the Trinity?